Based on the image of emulating a pet dog, the dated British-Army slang expression poodle-faker designates a ladies’ man.

This expression occurs, for example, in the following from the Chelsea News (London, England) of Friday 18^th September 1970:

Recalling the days of the poodle-fakers
Comment from an anonymous grandpop

Oh no, dear boy, things were not all that different in my day.
I served my apprenticeship as a poodle-faker, to use a with-it expression no longer current among you youngsters.
To be a poodle-faker you had to be a good-looking subaltern with a nice row of medals, a competence as a dancer, and a mess-dress that was not two [sic] moth-eaten.
You were then rewarded by being dispatched from some God-forsaken mud fort or bleak encampment, for a spell of duty in some stately residence, where you were expected to dance with the well-chaperoned daughters of duchesses and (oh dear) with all the dowagers as well.
One of these, introducing me to a nervous oriental lady who was technically in purdah, said kindly, “It is all right, my dear, this gentleman is a eunuch.”

The earliest occurrences of the expression poodle-faker that I have found are as follows, in chronological order:

1-: From A Famous Cavalry Regiment, about the 1^st Royal Dragoons, published in The Civil & Military Gazette (Lahore, Pakistan) of Thursday 25^th January 1900, reprinted from Cassell’s Magazine (London, England) of January 1900—the following is from the description of the officers’ mess:

In a mahogany case an old regimental diary of the time of the Peninsular War was most carefully [p]reserved. Much that was interesting and amusing is therein transcribed by various hands—details not of the gallant actions of the Royals, but of their hardships and the jokes they made about them, of the little tiffs amongst the officers, one man thinking he was worked too hard, another that he had been done in a horse-deal, and the like. Altogether a sidelight on the military life of those gallant gentlemen heroes of a score of battles, who were no “knights of the drawing-room,” no “poodle-fakers,” as the army slang has it, but soldiers who would far rather do a noble deed than describe how it came to be performed.

2-: From Letters to Ethel.—II., by ‘L.’, published in The Civil & Military Gazette (Lahore, Pakistan) of Tuesday 4^th January 1903:

My dearest Ethel,—l am awfully sorry I missed last mail, but I am quite sure if you had been in my place you would never have found time to write letters. I can’t tell you how much I like India, and I think Lucknow is one of the most fascinating places I ever was in. […] It has been very full lately of such jolly people from nearly everywhere in India, who come here for the Army Cup week. […] A Captain Allan came too, he belongs to the 24^th Lancers, and he is very good-looking and has lots of money. I think I shall like him, though he looks rather as if he were bored by most things in life. Major Strachey says he is a “good chap but a bit of a poodle faker,” but he calls everyone that who is nice to women and who takes one about, and goes to teas and things.

3-: From The Ordeal of Leaving the Regiment, by ‘Game-cock’, published in The Civil & Military Gazette (Lahore, Pakistan) of Saturday 19^th September 1903—the noun slackster is a variant of slacker, designating a person who shirks work, or avoids exertion, exercise, etc.:

Can it be only a fortnight ago that he had given vent to that little ebullition of temper that had made the others laugh just before lunch? Does he not remember how he had torn off his sword and hurled it into a corner (the dint is on the sword hilt now), and does he not remember shouting out furiously those words “Thank God this damnable life is nearly over.” Ah, but he had been maddened that day. Jerrold the man who had been promoted to Major over his head, who had never been a soldier, or anything but a poodle faker and a slackster, had ridden up to him—it was on Cove Common and had told him he must keep his men in hand better. He reddened in shame and fruitless anger as he thought of it now.

4-: From That Fraud Bilson, by ‘G. A. S.’, about a certain Bilson, who used to be regarded “as the greatest literary asset that the Colony [of Hong Kong] possessed”, published in the Overland China Mail (Hong Kong, China) of Saturday 28^th July 1906—note: nothing in this article by ‘G. A. S.’ suggests that Bilson was a ladies’ man:

I read that manuscript through from end to end. It contained not one word about Russia. It was addressed to the Editor of the Hongkong Clarion; the subject was “Civil Servants’ Salaries” and the signature was Pro Bono Publico. Two months later I learnt from Bilson’s messmate—there had been a quarrel and they had separated—that Bilson was a fraud, that this kind of gratuitous writing was the only kind he ever got published and that he had never appeared in print except under the original disguise of Pro Bono Publico.
I have knocked Bilson off his pedestal and am in search of a Hongkong hero—other than a poodle-faker or a bridge-player—whom I may set up and worship in his stead.

5-: From the following letter to the Editor, published in The Civil & Military Gazette (Lahore, Pakistan) of Sunday 23^rd September 1906:

POODLE-FAKING.

Sir,—The pathetic complaint of your subaltern contributor the other day, regarding his sad plight at a hill station, makes one tremble for the future of the army.
Is it really necessary for us to be attached to one or other lady’s petticoat strings? Surely there is still a shred of hope for those who prefer to remain unattached?
I read a little book the other day written by Captain Hayes, the well known horse-master, describing his life as a subaltern in India in the seventies or eighties. Every station then had its race course, not neglected, as is now the case, but raced on. And a splendid time the subalterns of those days had! Now our dainty little “poodle-fakers” look askance at racing, unless it take the form of a vile bun-fight, in which miserable crocks amble across a lawn in some absurd contest dignified with the name of race.
A praiseworthy attempt to revive gymkhana races in Pindi last cold weather was nearly frustrated altogether, because the “rank and fashion” accorded it the cold shoulder. Perhaps the fact that there was a Rs. 2 totalizator on the course frightened the anti-betting, pro-kiss-and-giggle officer away.
Backbone.